The background of the invention will be set forth in two parts.
1. FIELD OF THE INVENTION
The invention relates to surface acoustic wave devices and more particularly to surface acoustic wave notch filters.
2. DESCRIPTION OF THE PRIOR ART
Conventional LC circuits and most known active filter techniques have generally not proven to be very successful in VHF notch filter applications. In the past, surface acoustic wave devices have been designed to provide this valuable function. Basically, the most advantageous type of this class of notch filter uses nulls in transducer responses which occur periodically in frequency and thus cannot be arbitrarily placed. As can be seen, this is very limiting and an efficient surface acoustic wave notch filter that can be designed to provide a deep notch characteristic at any desired frequency in the pass band of a delay line would constitute a significant advancement of the art.